How does Java invoke the external interface? Take a simple post interface call as an example

In the Java C/S software development, docking a number of third-party provided web interface.

The way you use the interface is not as difficult as you might think.
For example, if the provided interface is a get form, the address is output directly on the Web page, and the parameters are pieced together to get the return value.
If it is a post interface, it is necessary to make a request for an interface, such as postman or the browser's own plug-in, and so on.
The same is true for code conversion.
Here is an example of a simple post interface invocation:
The P:param parameter can be used to pass in a Jsonobject.fromobject (object)

     /** * @author: CJD * @description: Post interface returns result String * @params: [URL, param] * @param URL Request interface * @param param JSON string required * @return: java.lang.String * @date: 17:31 2018/8/1 */public static string Sendpo        St (string URL, string param) {outputstreamwriter out = null;        BufferedReader in = null;        String result = "";            try {URL realurl = new URL (URL);            HttpURLConnection conn = null;            Connection between open and URL conn = (httpurlconnection) realurl.openconnection ();            The Send POST request must be set to the following two lines conn.setdooutput (true);            Conn.setdoinput (TRUE);    Conn.setrequestmethod ("POST");            Post method//Set general request attribute Conn.setrequestproperty ("accept", "*/*");            Conn.setrequestproperty ("Connection", "keep-alive"); Conn.setrequestproperty ("User-agent", "mozilla/4.0" (compatible; MSIE 6.0; Windows NT 5.1;            SV1) "); Conn.setrEquestproperty ("Content-type", "application/json;charset=utf-8");            Conn.connect ();            Gets the output stream corresponding to the URLConnection object out = new OutputStreamWriter (Conn.getoutputstream (), "UTF-8");            Send request parameter out.write (param);            Flush output Stream Buffer Out.flush ();            Defines the BufferedReader input stream to read the response of the URL in = new BufferedReader (New InputStreamReader (Conn.getinputstream ()));            String Line;            while (line = In.readline ()) = null) {result + = line; }} catch (Exception e) {System.out.println ("send POST request exception!            "+ e);        E.printstacktrace (); }//Use finally block to close the output stream, input stream finally {try {if (out! = null) {out                . Close ();                } if (in = null) {in.close ();            }} catch (IOException ex) {ex.printstacktrace (); }        }        return result; }

When the method is called, a string format for the returned JSON data is obtained.
Java is an object-oriented language, so using Jsonobject/jsonarray to convert the JSON data into an object of the entity class, for example I use, because the interface returned there is a bit strange, so I took a few steps to deal with the following:

            Prepickupmailres Resultbean = new Prepickupmailres ();            Jsonobject Respjson = Jsonobject.fromobject (Jsonobject.fromobject (JSON). Get ("Respjson"));            Jsonarray Jsonarray = (jsonarray) respjson.get ("Prepickuprspdetaildtolist");            Jsonobject Resultjson = (jsonobject) jsonarray.get (0);            Jsonutils.getmorpherregistry (). Registermorpher (New Datemorpher (New string[]{"Mm/dd/yyyy HH:mm:ss"});            Resultbean = (prepickupmailres) Jsonobject.tobean (Resultjson, Prepickupmailres.class);

So the last thing we get is an entity object.

For more information on how to use Jsonobject/jsonarray, see:
https://blog.csdn.net/chijiandi/article/details/81011369

C/S software development of Java, docking some third-party provided web interface. The way the
interfaces are used is not as difficult as it might seem.
For example, if the provided interface is a get form, the address is output directly on the Web page, and the parameters are pieced together to get the return value.
If it is a post interface, it is necessary to make a request for an interface, such as postman or browser-brought plug-ins, and so on. The
translates into code as well.
The following is a simple example of a post interface invocation:
The P:param parameter can be passed in with Jsonobject.fromobject (object) to the

     /** * @author: CJD * @description: Post interface returns result String * @params: [URL, param] * @param URL Request interface * @param param JSON string required * @return: java.lang.String * @date: 17:31 2018/8/1 */public static string Sendpo        St (string URL, string param) {outputstreamwriter out = null;        BufferedReader in = null;        String result = "";            try {URL realurl = new URL (URL);            HttpURLConnection conn = null;            Connection between open and URL conn = (httpurlconnection) realurl.openconnection ();            The Send POST request must be set to the following two lines conn.setdooutput (true);            Conn.setdoinput (TRUE);    Conn.setrequestmethod ("POST");            Post method//Set general request attribute Conn.setrequestproperty ("accept", "*/*");            Conn.setrequestproperty ("Connection", "keep-alive"); Conn.setrequestproperty ("User-agent", "mozilla/4.0" (compatible; MSIE 6.0; Windows NT 5.1;            SV1) "); Conn.setrEquestproperty ("Content-type", "application/json;charset=utf-8");            Conn.connect ();            Gets the output stream corresponding to the URLConnection object out = new OutputStreamWriter (Conn.getoutputstream (), "UTF-8");            Send request parameter out.write (param);            Flush output Stream Buffer Out.flush ();            Defines the BufferedReader input stream to read the response of the URL in = new BufferedReader (New InputStreamReader (Conn.getinputstream ()));            String Line;            while (line = In.readline ()) = null) {result + = line; }} catch (Exception e) {System.out.println ("send POST request exception!            "+ e);        E.printstacktrace (); }//Use finally block to close the output stream, input stream finally {try {if (out! = null) {out                . Close ();                } if (in = null) {in.close ();            }} catch (IOException ex) {ex.printstacktrace (); }        }        return result; }

When the method is called, a string format for the returned JSON data is obtained.
Java is an object-oriented language, so using Jsonobject/jsonarray to convert the JSON data into an object of the entity class, for example I use, because the interface returned there is a bit strange, so I took a few steps to deal with the following:

            Prepickupmailres Resultbean = new Prepickupmailres ();            Jsonobject Respjson = Jsonobject.fromobject (Jsonobject.fromobject (JSON). Get ("Respjson"));            Jsonarray Jsonarray = (jsonarray) respjson.get ("Prepickuprspdetaildtolist");            Jsonobject Resultjson = (jsonobject) jsonarray.get (0);            Jsonutils.getmorpherregistry (). Registermorpher (New Datemorpher (New string[]{"Mm/dd/yyyy HH:mm:ss"});            Resultbean = (prepickupmailres) Jsonobject.tobean (Resultjson, Prepickupmailres.class);

So the last thing we get is an entity object.

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